A real estate agent is considering changing her cell phone plan. there are 3 plans to choose from, all of which involve a weekly service charge of $20. plan A has a cost of $0.45/min for daytime calls and $0.20/min for evening calls. plan B has a charge of $0.55/min for daytime calls and $0.15/min for evening calls. plan C has a flat rate of $80 with 200 minutes of calls allowed per week and a charge of $0.40 per minute beyond that, day or evening ?
Determine the total charge under each plan for this case: 120 minutes of daytime call minutes.?
Prepare a graph that shows total weekly cost for each plan versus daytime call minutes.?
If Davie will use the service for daytime calls, over what range of call minutes will each plan be optimal?